The Creole community in New Orleans sported any number of highly skilled craftsmen. I think they'd roll their eyes if they saw how their skills are reproduced in miniature!
Here is a look at how the bousillage was done. In a real house, all of the spaces between the beams would have been filled with soft blobs of mud and Spanish moss and left to dry before an outer coat of plaster was applied. In mini, however, all we need is a glimpse, a place where the plaster has fallen away. All of the space between the beams was filled with wallboard mud (aka joint compound).
In the third photo, you can see the results of the painting and aging process. You can also see the oyster shells beneath the house. Crushed eggshells make a suitable stand-in. Oyster shells are a cheap commodity in New Orleans and were used around and under houses to reduce mud and dust.
The last photo today shows the "brick" pillars that the house stands are. Most houses in New Orleans are raised, both for the cooling effect of air passing beneath the floors in the summer and as a guard against flooding. These pillars are made of 1" square wood dowels painted to look like bricks.
The ceiling in the parlor shows the wood ceiling beams and the wood planking of the attic floor. It is painted Paris green, very typical of the time. The bedroom ceiling has been painted with white gesso. It will have beams added later.